1
|
Sharma V, Ali MF, Kawashima T. Insights into dynamic coenocytic endosperm development: Unraveling molecular, cellular, and growth complexity. CURRENT OPINION IN PLANT BIOLOGY 2024; 81:102566. [PMID: 38830335 DOI: 10.1016/j.pbi.2024.102566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Revised: 05/02/2024] [Accepted: 05/13/2024] [Indexed: 06/05/2024]
Abstract
The endosperm, a product of double fertilization, is one of the keys to the evolution and success of angiosperms in conquering the land. While there are differences in endosperm development among flowering plants, the most common form is coenocytic growth, where the endosperm initially undergoes nuclear division without cytokinesis and eventually becomes cellularized. This complex process requires interplay among networks of transcription factors such as MADS-box, auxin response factors (ARFs), and phytohormones. The role of cytoskeletal elements in shaping the coenocytic endosperm and influencing seed growth also becomes evident. This review offers a recent understanding of the molecular and cellular dynamics in coenocytic endosperm development and their contributions to the final seed size.
Collapse
Affiliation(s)
- Vijyesh Sharma
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY, USA
| | - Mohammad Foteh Ali
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY, USA
| | - Tomokazu Kawashima
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY, USA.
| |
Collapse
|
2
|
Bessho K, Sasaki A. Evolution of parental care in haploid-diploid plants. Proc Biol Sci 2024; 291:20232351. [PMID: 38351800 PMCID: PMC10865002 DOI: 10.1098/rspb.2023.2351] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 01/16/2024] [Indexed: 02/16/2024] Open
Abstract
In bryophytes that alternate between haploid gametophytes and diploid sporophytes through sexual reproduction, sporophytes are often attached to and nurtured on the female gametophyte. A similar phenomenon is seen in Florideophyceae (a group of red algae). These systems in which a gametophyte (mother) invests nutrients in sporophytes (offspring) are ideal for studying the evolution of 'parental care' in non-animal organisms. Here, we propose a model of a haploid-diploid life cycle and examine the evolution of maternal investment in sporophytes focusing on two effects: the degree of paternal or maternal control of investment and the number of sporophytes. We find that when the female dominantly controls the investment, the evolutionarily stable level of investment is that which maximizes the expected reproductive success of the female gametophyte. The genomic conflict between maternal and paternal alleles complicates the evolutionary outcome; however, a greater male allelic effect and a higher number of sporophytes favour a higher energy investment, which may lead to evolutionary branching or run-away escalation of the investment level. This suggests that the selfishness of the paternal gene is the evolutionary driver of parental care and that complex structures such as fusion cells in red algae may have evolved to suppress it.
Collapse
Affiliation(s)
- Kazuhiro Bessho
- Medical Research Center, Saitama Medical University, 38 Morohongo Moroyama-machi, Iruma-gun, Saitama 350-0495, Japan
| | - Akira Sasaki
- Research Center for Integrative Evolutionary Science, The Graduate University for Advanced Studies, SOKENDAI, Hayama, Kanagawa 240-0193, Japan
- Evolution and Ecology Program, International Institute for Applied Systems Analysis, Schlosplatz 1, Laxenburg 2361, Austria
| |
Collapse
|
3
|
Montgomery SA, Berger F. Paternal imprinting in Marchantia polymorpha. THE NEW PHYTOLOGIST 2024; 241:1000-1006. [PMID: 37936346 DOI: 10.1111/nph.19377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 10/09/2023] [Indexed: 11/09/2023]
Abstract
We are becoming aware of a growing number of organisms that do not express genetic information equally from both parents as a result of an epigenetic phenomenon called genomic imprinting. Recently, it was shown that the entire paternal genome is repressed during the diploid phase of the life cycle of the liverwort Marchantia polymorpha. The deposition of the repressive epigenetic mark H3K27me3 on the male pronucleus is responsible for the imprinted state, which is reset by the end of meiosis. Here, we put these recent reports in perspective of other forms of imprinting and discuss the potential mechanisms of imprinting in bryophytes and the causes of its evolution.
Collapse
Affiliation(s)
- Sean A Montgomery
- Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), C/ del Dr Aiguader, 88, 08003, Barcelona, Spain
| | - Frédéric Berger
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, Dr Bohr-Gasse 3, 1030, Vienna, Austria
| |
Collapse
|
4
|
He Y, Bader MY, Li D, Stark LR, Li X, Liu X, Yuan Q, Guo S, Fang Z, Wang Z. Relationships among sporophytic and gametophytic traits of 27 subtropical montane moss species. AMERICAN JOURNAL OF BOTANY 2023; 110:e16253. [PMID: 37938812 DOI: 10.1002/ajb2.16253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 10/15/2023] [Accepted: 10/16/2023] [Indexed: 11/10/2023]
Abstract
PREMISE Moss sporophytes differ strongly in size and biomass partitioning, potentially reflecting reproductive and dispersal strategies. Understanding how sporophyte traits are coordinated is essential for understanding moss functioning and evolution. This study aimed to answer: (1) how the size and proportions of the sporophyte differ between moss species with and without a prominent central strand in the seta, (2) how anatomical and morphological traits of the seta are related, and (3) how sporophytic biomass relates to gametophytic biomass and nutrient concentrations. METHODS We studied the relationships between seta anatomical and morphological traits, the biomass of seta, capsule, and gametophyte, and carbon, nitrogen, and phosphorus concentrations of 27 subtropical montane moss species. RESULTS (1) Moss species with a prominent central strand in the seta had larger setae and heavier capsules than those without a prominent strand. (2) With increasing seta length, setae became thicker and more rounded for both groups, while in species with a prominent central strand, the ratio of transport-cell area to epidermal area decreased. (3) In both groups, mosses with greater gametophytic biomass tended to have heavier sporophytes, but nitrogen and phosphorus concentrations in the gametophyte were unrelated to sporophytic traits. CONCLUSIONS Our study highlights that the central strand in the seta may have an important functional role and affect the allometry of moss sporophytes. The coordinated variations in sporophyte morphological and anatomical traits follow basic biomechanical principles of cylinder-like structures, and these traits relate only weakly to the gametophytic nutrient concentrations. Research on moss sporophyte functional traits and their relationships to gametophytes is still in its infancy but could provide important insights into their adaptative strategies.
Collapse
Affiliation(s)
- Yunyu He
- Shanghai Normal University, Shanghai, 200234, China
| | - Maaike Y Bader
- Ecological Plant Geography, Faculty of Geography, University of Marburg, Marburg, 35032, Germany
| | - Dandan Li
- Shanghai Normal University, Shanghai, 200234, China
| | - Lloyd R Stark
- School of Life Sciences, University of Nevada, Las Vegas, NV, 89154-4004, USA
| | - Xiaoming Li
- China-Croatia "Belt and Road" Joint Laboratory on Biodiversity and Ecosystem Services, CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chinese Academy of Sciences, Chengdu, 610041, China
| | - Xin Liu
- China-Croatia "Belt and Road" Joint Laboratory on Biodiversity and Ecosystem Services, CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chinese Academy of Sciences, Chengdu, 610041, China
| | - Qizhang Yuan
- Shanghai Normal University, Shanghai, 200234, China
| | | | - Zhiqiang Fang
- Sichuan Provincial Academy of Natural Resources Sciences, Chengdu, 610041, China
| | - Zhe Wang
- Shanghai Normal University, Shanghai, 200234, China
| |
Collapse
|
5
|
McDaniel SF. Divergent outcomes of genetic conflict on the UV sex chromosomes of Marchantia polymorpha and Ceratodon purpureus. Curr Opin Genet Dev 2023; 83:102129. [PMID: 37864936 DOI: 10.1016/j.gde.2023.102129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 09/22/2023] [Accepted: 09/24/2023] [Indexed: 10/23/2023]
Abstract
In species with separate sexes, the genome must produce two distinct developmental programs. Sexually dimorphic development may be controlled by either sex-limited loci or biased expression of loci transmitted through both sexes. Variation in the gene content of sex-limited chromosomes demonstrates that eukaryotic species differ markedly in the roles of these two mechanisms in governing sexual dimorphism. The bryophyte model systems Marchantia polymorpha and Ceratodon purpureus provide a particularly striking contrast. Although both species possess a haploid UV sex chromosome system, in which females carry a U chromosome and males carry a V, M. polymorpha relies on biased autosomal expression, while in C. purpureus, sex-linked genes drive dimorphism. Framing these genetic architectures as divergent outcomes of genetic conflict highlights comparative genomic analyses to better understand the evolution of sexual dimorphism.
Collapse
Affiliation(s)
- Stuart F McDaniel
- Biology Department, University of Florida, Gainesville, FL 32611-8525, USA.
| |
Collapse
|
6
|
Bisang I, Ehrlén J, Hedenäs L. Life-history characteristics and historical factors are important to explain regional variation in reproductive traits and genetic diversity in perennial mosses. ANNALS OF BOTANY 2023; 132:29-42. [PMID: 36928083 PMCID: PMC10550275 DOI: 10.1093/aob/mcad045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 03/15/2023] [Indexed: 06/18/2023]
Abstract
BACKGROUND AND AIMS Plants have evolved an unrivalled diversity of reproductive strategies, including variation in the degree of sexual vs. clonal reproduction. This variation has important effects on the dynamics and genetic structure of populations. We examined the association between large-scale variation in reproductive patterns and intraspecific genetic diversity in two moss species where sex is manifested in the dominant haploid generation and sex expression is irregular. We predicted that in regions with more frequent realized sexual reproduction, populations should display less skewed sex ratios, should more often express sex and should have higher genetic diversity than in regions with largely clonal reproduction. METHODS We assessed reproductive status and phenotypic sex in the dioicous long-lived Drepanocladus trifarius and D. turgescens, in 248 and 438 samples across two regions in Scandinavia with frequent or rare realized sexual reproduction, respectively. In subsets of the samples, we analysed genetic diversity using nuclear and plastid sequence information and identified sex with a sex-specific molecular marker in non-reproductive samples. KEY RESULTS Contrary to our predictions, sex ratios did not differ between regions; genetic diversity did not differ in D. trifarius and it was higher in the region with rare sexual reproduction in D. turgescens. Supporting our predictions, relatively more samples expressed sex in D. trifarius in the region with frequent sexual reproduction. Overall, samples were mostly female. The degree of sex expression and genetic diversity differed between sexes. CONCLUSIONS Sex expression levels, regional sex ratios and genetic diversity were not directly associated with the regional frequency of realized sexual reproduction, and relationships and variation patterns differed between species. We conclude that a combination of species-specific life histories, such as longevity, overall degree of successful sexual reproduction and recruitment, and historical factors are important to explain this variation. Our data on haploid-dominated plants significantly complement plant reproductive biology.
Collapse
Affiliation(s)
- Irene Bisang
- Department of Botany, Swedish Museum of Natural History, Box 50007, SE-104 05 Stockholm, Sweden
| | - Johan Ehrlén
- Department of Ecology, Environment and Plant Sciences, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Lars Hedenäs
- Department of Botany, Swedish Museum of Natural History, Box 50007, SE-104 05 Stockholm, Sweden
| |
Collapse
|
7
|
Montgomery SA, Hisanaga T, Wang N, Axelsson E, Akimcheva S, Sramek M, Liu C, Berger F. Polycomb-mediated repression of paternal chromosomes maintains haploid dosage in diploid embryos of Marchantia. eLife 2022; 11:79258. [PMID: 35996955 PMCID: PMC9402228 DOI: 10.7554/elife.79258] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 07/18/2022] [Indexed: 02/06/2023] Open
Abstract
Complex mechanisms regulate gene dosage throughout eukaryotic life cycles. Mechanisms controlling gene dosage have been extensively studied in animals, however it is unknown how generalizable these mechanisms are to diverse eukaryotes. Here, we use the haploid plant Marchantia polymorpha to assess gene dosage control in its short-lived diploid embryo. We show that throughout embryogenesis, paternal chromosomes are repressed resulting in functional haploidy. The paternal genome is targeted for genomic imprinting by the Polycomb mark H3K27me3 starting at fertilization, rendering the maternal genome in control of embryogenesis. Maintaining haploid gene dosage by this new form of imprinting is essential for embryonic development. Our findings illustrate how haploid-dominant species can regulate gene dosage through paternal chromosome inactivation and initiates the exploration of the link between life cycle history and gene dosage in a broader range of organisms.
Collapse
Affiliation(s)
- Sean Akira Montgomery
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, Vienna, Austria.,Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna, Austria
| | - Tetsuya Hisanaga
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, Vienna, Austria
| | - Nan Wang
- Institute of Biology, University of Hohenheim, Stuttgart, Germany
| | - Elin Axelsson
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, Vienna, Austria
| | - Svetlana Akimcheva
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, Vienna, Austria
| | - Milos Sramek
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, Vienna, Austria
| | - Chang Liu
- Institute of Biology, University of Hohenheim, Stuttgart, Germany
| | - Frédéric Berger
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, Vienna, Austria
| |
Collapse
|
8
|
Sorojsrisom ES, Haller BC, Ambrose BA, Eaton DAR. Selection on the gametophyte: Modeling alternation of generations in plants. APPLICATIONS IN PLANT SCIENCES 2022; 10:e11472. [PMID: 35495198 PMCID: PMC9039789 DOI: 10.1002/aps3.11472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 03/14/2022] [Indexed: 05/12/2023]
Abstract
PREMISE The degree of gametophyte dependence on the sporophyte life stage is a major feature that differentiates the life cycles of land plants, yet the evolutionary consequences of this difference remain poorly understood. Most evolutionary models assume organisms are either haploid or diploid for their entire lifespan, which is not appropriate for simulating plant life cycles. Here, we introduce shadie (Simulating Haploid-Diploid Evolution), a new, simple Python program for implementing simulations with biphasic life cycles and analyzing their results, using SLiM 3 as a simulation back end. METHODS We implemented evolutionary simulations under three realistic plant life cycle models supported in shadie, using either standardized or biologically realistic parameter settings to test how variation in plant life cycles and sexual systems affects patterns of genome diversity. RESULTS The dynamics of single beneficial mutation fixation did not vary dramatically between different models, but the patterns of spatial variation did differ, demonstrating that different life histories and model parameters affect both genetic diversity and linkage disequilibrium. The rate of linkage disequilibrium decay away from selected sites varied depending on model parameters such as cloning and selfing rates, through their impact on effective population sizes. DISCUSSION Evolutionary simulations are an exciting, underutilized approach in evolutionary research and education. shadie can aid plant researchers in developing null hypotheses, examining theory, and designing empirical studies, in order to investigate the role of the gametophyte life stage, and the effects of variation in plant life cycles, on plant genome evolution.
Collapse
Affiliation(s)
- Elissa S. Sorojsrisom
- Department of Ecology, Evolution, and Environmental BiologyColumbia University1200 Amsterdam Ave., Schermerhorn Ext.New York10027USA
- New York Botanical Garden2900 Southern Blvd.BronxNew York10458USA
| | - Benjamin C. Haller
- Department of Computational BiologyCornell University, IthacaNew York14853USA
| | | | - Deren A. R. Eaton
- Department of Ecology, Evolution, and Environmental BiologyColumbia University1200 Amsterdam Ave., Schermerhorn Ext.New York10027USA
| |
Collapse
|
9
|
Montgomery SA, Berger F. The evolution of imprinting in plants: beyond the seed. PLANT REPRODUCTION 2021; 34:373-383. [PMID: 33914165 PMCID: PMC8566399 DOI: 10.1007/s00497-021-00410-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 04/12/2021] [Indexed: 05/14/2023]
Abstract
Genomic imprinting results in the biased expression of alleles depending on if the allele was inherited from the mother or the father. Despite the prevalence of sexual reproduction across eukaryotes, imprinting is only found in placental mammals, flowering plants, and some insects, suggesting independent evolutionary origins. Numerous hypotheses have been proposed to explain the selective pressures that favour the innovation of imprinted gene expression and each differs in their experimental support and predictions. Due to the lack of investigation of imprinting in land plants, other than angiosperms with triploid endosperm, we do not know whether imprinting occurs in species lacking endosperm and with embryos developing on maternal plants. Here, we discuss the potential for uncovering additional examples of imprinting in land plants and how these observations may provide additional support for one or more existing imprinting hypotheses.
Collapse
Affiliation(s)
- Sean A Montgomery
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC), Dr. Bohr Gasse 3, 1030, Vienna, Austria
| | - Frédéric Berger
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC), Dr. Bohr Gasse 3, 1030, Vienna, Austria.
| |
Collapse
|
10
|
Vigneau J, Borg M. The epigenetic origin of life history transitions in plants and algae. PLANT REPRODUCTION 2021; 34:267-285. [PMID: 34236522 PMCID: PMC8566409 DOI: 10.1007/s00497-021-00422-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 06/14/2021] [Indexed: 05/17/2023]
Abstract
Plants and algae have a complex life history that transitions between distinct life forms called the sporophyte and the gametophyte. This phenomenon-called the alternation of generations-has fascinated botanists and phycologists for over 170 years. Despite the mesmerizing array of life histories described in plants and algae, we are only now beginning to learn about the molecular mechanisms controlling them and how they evolved. Epigenetic silencing plays an essential role in regulating gene expression during multicellular development in eukaryotes, raising questions about its impact on the life history strategy of plants and algae. Here, we trace the origin and function of epigenetic mechanisms across the plant kingdom, from unicellular green algae through to angiosperms, and attempt to reconstruct the evolutionary steps that influenced life history transitions during plant evolution. Central to this evolutionary scenario is the adaption of epigenetic silencing from a mechanism of genome defense to the repression and control of alternating generations. We extend our discussion beyond the green lineage and highlight the peculiar case of the brown algae. Unlike their unicellular diatom relatives, brown algae lack epigenetic silencing pathways common to animals and plants yet display complex life histories, hinting at the emergence of novel life history controls during stramenopile evolution.
Collapse
Affiliation(s)
- Jérômine Vigneau
- Department of Algal Development and Evolution, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Michael Borg
- Department of Algal Development and Evolution, Max Planck Institute for Developmental Biology, Tübingen, Germany.
| |
Collapse
|
11
|
Meissner ST. Plant sexual reproduction: perhaps the current plant two-sex model should be replaced with three- and four-sex models? PLANT REPRODUCTION 2021; 34:175-189. [PMID: 34213647 PMCID: PMC8360875 DOI: 10.1007/s00497-021-00420-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2020] [Accepted: 06/07/2021] [Indexed: 06/12/2023]
Abstract
The two-sex model makes the assumption that there are only two sexual reproductive states: male and female. However, in land plants (embryophytes) the application of this model to the alternation of generations life cycle requires the subtle redefinition of several common terms related to sexual reproduction, which seems to obscure aspects of one or the other plant generation: For instance, the homosporous sporophytic plant is treated as being asexual, and the gametophytes of angiosperms treated like mere gametes. In contrast, the proposal is made that the sporophytes of homosporous plants are indeed sexual reproductive organisms, as are the gametophytes of heterosporous plants. This view requires the expansion of the number of sexual reproductive states we accept for these plant species; therefore, a three-sex model for homosporous plants and a four-sex model for heterosporous plants are described and then contrasted with the current two-sex model. These new models allow the use of sexual reproductive terms in a manner largely similar to that seen in animals, and may better accommodate the plant alternation of generations life cycle than does the current plant two-sex model. These new models may also help stimulate new lines of research, and examples of how they might alter our view of events in the flower, and may lead to new questions about sexual determination and differentiation, are presented. Thus it is suggested that land plant species have more than merely two sexual reproductive states and that recognition of this may promote our study and understanding of them.
Collapse
Affiliation(s)
- Scott T Meissner
- Institute of Biology, University of the Philippines Diliman, 1101, Quezon City, NCR, Philippines.
| |
Collapse
|
12
|
Shortlidge EE, Carey SB, Payton AC, McDaniel SF, Rosenstiel TN, Eppley SM. Microarthropod contributions to fitness variation in the common moss Ceratodon purpureus. Proc Biol Sci 2021; 288:20210119. [PMID: 33784868 PMCID: PMC8059975 DOI: 10.1098/rspb.2021.0119] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The evolution of sustained plant–animal interactions depends critically upon genetic variation in the fitness benefits from the interaction. Genetic analyses of such interactions are limited to a few model systems, in part because genetic variation may be absent or the interacting species may be experimentally intractable. Here, we examine the role of sperm-dispersing microarthropods in shaping reproduction and genetic variation in mosses. We established experimental mesocosms with known moss genotypes and inferred the parents of progeny from mesocosms with and without microarthropods, using a pooled sequencing approach. Moss reproductive rates increased fivefold in the presence of microarthropods, relative to control mesocosms. Furthermore, the presence of microarthropods increased the total number of reproducing moss genotypes, and changed the rank-order of fitness of male and female moss genotypes. Interestingly, the genotypes that reproduced most frequently did not produce sporophytes with the most spores, highlighting the challenge of defining fitness in mosses. These results demonstrate that microarthropods provide a fitness benefit for mosses, and highlight the potential for biotic dispersal agents to alter fitness among moss genotypes.
Collapse
Affiliation(s)
- Erin E Shortlidge
- Department of Biology, Portland State University, PO Box 751, Portland, OR 97202-0751, USA
| | - Sarah B Carey
- Department of Biology, University of Florida, PO Box 118525, Gainesville, FL 32611-8525, USA
| | - Adam C Payton
- Department of Biology, University of Florida, PO Box 118525, Gainesville, FL 32611-8525, USA
| | - Stuart F McDaniel
- Department of Biology, University of Florida, PO Box 118525, Gainesville, FL 32611-8525, USA
| | - Todd N Rosenstiel
- Department of Biology, Portland State University, PO Box 751, Portland, OR 97202-0751, USA
| | - Sarah M Eppley
- Department of Biology, Portland State University, PO Box 751, Portland, OR 97202-0751, USA
| |
Collapse
|
13
|
Faria GS, Varela SAM, Gardner A. Sexual selection modulates genetic conflicts and patterns of genomic imprinting. Evolution 2017; 71:526-540. [PMID: 27991659 PMCID: PMC5347858 DOI: 10.1111/evo.13153] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 12/03/2016] [Indexed: 12/16/2022]
Abstract
Recent years have seen a surge of interest in linking the theories of kin selection and sexual selection. In particular, there is a growing appreciation that kin selection, arising through demographic factors such as sex-biased dispersal, may modulate sexual conflicts, including in the context of male-female arms races characterized by coevolutionary cycles. However, evolutionary conflicts of interest need not only occur between individuals, but may also occur within individuals, and sex-specific demography is known to foment such intragenomic conflict in relation to social behavior. Whether and how this logic holds in the context of sexual conflict-and, in particular, in relation to coevolutionary cycles-remains obscure. We develop a kin-selection model to investigate the interests of different genes involved in sexual and intragenomic conflict, and we show that consideration of these conflicting interests yields novel predictions concerning parent-of-origin specific patterns of gene expression and the detrimental effects of different classes of mutation and epimutation at loci underpinning sexually selected phenotypes.
Collapse
Affiliation(s)
- Gonçalo S. Faria
- School of BiologyUniversity of St AndrewsDyers Brae, St AndrewsKY16 9THUnited Kingdom
| | - Susana A. M. Varela
- cE3c—Centre for Ecology, Evolution and Environmental Changes, Faculdade de CiênciasUniversidade de LisboaCampo Grande1749‐016LisboaPortugal
| | - Andy Gardner
- School of BiologyUniversity of St AndrewsDyers Brae, St AndrewsKY16 9THUnited Kingdom
| |
Collapse
|
14
|
Macaisne N, Liu F, Scornet D, Peters AF, Lipinska A, Perrineau MM, Henry A, Strittmatter M, Coelho SM, Cock JM. The Ectocarpus IMMEDIATE UPRIGHT gene encodes a member of a novel family of cysteine-rich proteins with an unusual distribution across the eukaryotes. Development 2017; 144:409-418. [PMID: 28049657 DOI: 10.1242/dev.141523] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 12/12/2016] [Indexed: 01/09/2023]
Abstract
The sporophyte generation of the brown alga Ectocarpus sp. exhibits an unusual pattern of development compared with the majority of brown algae. The first cell division is symmetrical and the apical-basal axis is established late in development. In the immediate upright (imm) mutant, the initial cell undergoes an asymmetric division to immediately establish the apical-basal axis. We provide evidence which suggests that this phenotype corresponds to the ancestral state of the sporophyte. The IMM gene encodes a protein of unknown function that contains a repeated motif also found in the EsV-1-7 gene of the Ectocarpus virus EsV-1. Brown algae possess large families of EsV-1-7 domain genes but these genes are rare in other stramenopiles, suggesting that the expansion of this family might have been linked with the emergence of multicellular complexity. EsV-1-7 domain genes have a patchy distribution across eukaryotic supergroups and occur in several viral genomes, suggesting possible horizontal transfer during eukaryote evolution.
Collapse
Affiliation(s)
- Nicolas Macaisne
- CNRS, Sorbonne Université, UPMC University Paris 06, Algal Genetics Group, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, Roscoff F-29688, France
| | - Fuli Liu
- CNRS, Sorbonne Université, UPMC University Paris 06, Algal Genetics Group, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, Roscoff F-29688, France
| | - Delphine Scornet
- CNRS, Sorbonne Université, UPMC University Paris 06, Algal Genetics Group, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, Roscoff F-29688, France
| | | | - Agnieszka Lipinska
- CNRS, Sorbonne Université, UPMC University Paris 06, Algal Genetics Group, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, Roscoff F-29688, France
| | - Marie-Mathilde Perrineau
- CNRS, Sorbonne Université, UPMC University Paris 06, Algal Genetics Group, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, Roscoff F-29688, France
| | - Antoine Henry
- CNRS, Sorbonne Université, UPMC University Paris 06, Algal Genetics Group, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, Roscoff F-29688, France
| | - Martina Strittmatter
- CNRS, Sorbonne Université, UPMC University Paris 06, Algal Genetics Group, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, Roscoff F-29688, France
| | - Susana M Coelho
- CNRS, Sorbonne Université, UPMC University Paris 06, Algal Genetics Group, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, Roscoff F-29688, France
| | - J Mark Cock
- CNRS, Sorbonne Université, UPMC University Paris 06, Algal Genetics Group, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, Roscoff F-29688, France
| |
Collapse
|
15
|
Scott MF, Rescan M. Evolution of haploid-diploid life cycles when haploid and diploid fitnesses are not equal. Evolution 2016; 71:215-226. [DOI: 10.1111/evo.13125] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2015] [Accepted: 10/26/2016] [Indexed: 01/28/2023]
Affiliation(s)
- Michael F Scott
- Department of Botany; University of British Columbia; Vancouver BC V6T 1Z4 Canada
| | - Marie Rescan
- CNRS, Unité Mixte Internationale 3614; Evolutionary Biology and Ecology of Algae; Roscoff France
- Végétaux marins et biomolécules, Sorbonne Universités, Université Pierre et Marie Curie; University of Paris 6; Roscoff France
| |
Collapse
|
16
|
Vreeburg S, Nygren K, Aanen DK. Unholy marriages and eternal triangles: how competition in the mushroom life cycle can lead to genomic conflict. Philos Trans R Soc Lond B Biol Sci 2016; 371:20150533. [PMID: 27619697 PMCID: PMC5031618 DOI: 10.1098/rstb.2015.0533] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/22/2016] [Indexed: 11/30/2022] Open
Abstract
In the vast majority of sexual life cycles, fusion between single-celled gametes is directly followed by nuclear fusion, leading to a diploid zygote and a lifelong commitment between two haploid genomes. Mushroom-forming basidiomycetes differ in two key respects. First, the multicellular haploid mating partners are fertilized in their entirety, each cell being a gamete that simultaneously can behave as a female, i.e. contributing the cytoplasm to a zygote by accepting nuclei, and a male gamete, i.e. only donating nuclei to the zygote. Second, after gamete union, the two haploid genomes remain separate so that the main vegetative stage, the dikaryon, has two haploid nuclei per cell. Only when the dikaryon produces mushrooms, do the nuclei fuse to enter a short diploid stage, immediately followed by meiosis and haploid spore formation. So in basidiomycetes, gamete fusion and genome mixing (sex) are separated in time. The 'living apart together' of nuclei in the dikaryon maintains some autonomy for nuclei to engage in a relationship with a different nucleus. We show that competition among the two nuclei of the dikaryon for such 'extramarital affairs' may lead to genomic conflict by favouring genes beneficial at the level of the nucleus, but deleterious at that of the dikaryon.This article is part of the themed issue 'Weird sex: the underappreciated diversity of sexual reproduction'.
Collapse
Affiliation(s)
- Sabine Vreeburg
- Laboratory of Genetics, Plant Sciences Group, Wageningen University, 6700 AA Wageningen, The Netherlands
| | - Kristiina Nygren
- Laboratory of Genetics, Plant Sciences Group, Wageningen University, 6700 AA Wageningen, The Netherlands
| | - Duur K Aanen
- Laboratory of Genetics, Plant Sciences Group, Wageningen University, 6700 AA Wageningen, The Netherlands
| |
Collapse
|
17
|
Budke JM, Goffinet B. Comparative Cuticle Development Reveals Taller Sporophytes Are Covered by Thicker Calyptra Cuticles in Mosses. FRONTIERS IN PLANT SCIENCE 2016; 7:832. [PMID: 27379125 PMCID: PMC4906049 DOI: 10.3389/fpls.2016.00832] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 05/27/2016] [Indexed: 05/18/2023]
Abstract
The calyptra is a maternal structure that protects the sporophyte offspring from dehydration, and positively impacts sporophyte survival and fitness in mosses. We explore the relationship between cuticle protection and sporophyte height as a proxy for dehydration stress in Funariaceae species with sporophytes across a range of sizes. Calyptrae and sporophytes from four species were collected from laboratory-grown populations at two developmental stages. Tissues were embedded, sectioned, and examined using transmission electron microscopy. Cuticle thickness was measured from three epidermal cells per organ for each individual and compared statistically. All four species have cuticles consisting of a cuticle proper and a cuticular layer on the calyptra and sporophyte at both developmental stages. Across species, shorter sporophytes are associated with smaller calyptra and thinner calyptra cuticles, whereas taller sporophytes are associated with larger calyptra and thicker calyptra cuticles. Independent of size, young sporophytes have a thin cuticle that thickens later during development, while calyptrae have a mature cuticle produced early during development that persists throughout development. This study adds to our knowledge of maternal effects influencing offspring survival in plants. Released from the pressures to invest in protection for their sporophyte offspring, maternal resources can be allocated to other processes that support sporophyte reproductive success. Using a comparative developmental framework enables us to broaden our understanding of cuticle development across species and provides structural evidence supporting the waterproofing role of the moss calyptra.
Collapse
Affiliation(s)
- Jessica M. Budke
- Department of Plant Biology, University of California, Davis, DavisCA, USA
| | - Bernard Goffinet
- Department of Ecology and Evolutionary Biology, University of Connecticut, StorrsCT, USA
| |
Collapse
|
18
|
Johnson MG, Shaw AJ. The effects of quantitative fecundity in the haploid stage on reproductive success and diploid fitness in the aquatic peat moss Sphagnum macrophyllum. Heredity (Edinb) 2016; 116:523-30. [PMID: 26905464 DOI: 10.1038/hdy.2016.13] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2015] [Revised: 11/23/2015] [Accepted: 12/29/2015] [Indexed: 11/09/2022] Open
Abstract
A major question in evolutionary biology is how mating patterns affect the fitness of offspring. However, in animals and seed plants it is virtually impossible to investigate the effects of specific gamete genotypes. In bryophytes, haploid gametophytes grow via clonal propagation and produce millions of genetically identical gametes throughout a population. The main goal of this research was to test whether gamete identity has an effect on the fitness of their diploid offspring in a population of the aquatic peat moss Sphagnum macrophyllum. We observed a heavily male-biased sex ratio in gametophyte plants (ramets) and in multilocus microsatellite genotypes (genets). There was a steeper relationship between mating success (number of different haploid mates) and fecundity (number of diploid offspring) for male genets compared with female genets. At the sporophyte level, we observed a weak effect of inbreeding on offspring fitness, but no effect of brood size (number of sporophytes per maternal ramet). Instead, the identities of the haploid male and haploid female parents were significant contributors to variance in fitness of sporophyte offspring in the population. Our results suggest that intrasexual gametophyte/gamete competition may play a role in determining mating success in this population.
Collapse
Affiliation(s)
- M G Johnson
- Department of Biology, Duke University, Durham, NC, USA
| | - A J Shaw
- Department of Biology, Duke University, Durham, NC, USA
| |
Collapse
|
19
|
Abstract
UNLABELLED • PREMISE OF THE STUDY Zygotes of Coleochaete are provisioned by the maternal thallus before undergoing 3-5 rounds of division to produce 8-32 zoospores. An understanding of the selective forces favoring postzygotic divisions would be relevant not only to the interpretation of Coleochaete life history but also to the origin of a multicellular diploid phase in embryophytes.• METHODS Simple optimization models are developed of the number of zygotes per maternal thallus and number of zoospores per zygote.• KEY RESULTS Zygotic mitosis is favored once zygotic size exceeds a threshold, but natural selection usually promotes investment in additional zygotes before zygotes reach this threshold. Factors that favor production of fewer, larger zygotes include multiple paternity, low fecundity, and accessory costs of zygote production. Such factors can result in zygotes exceeding the size at which zygotic mitosis becomes profitable.• CONCLUSIONS Coleochaete may possess large zygotes that undergo multiple fission because of accessory costs associated with matrotrophy, including costs of cortical cells and unfertilized oogonia. The unpredictability of fertilization on land is proposed to have increased accessory costs from unfertilized ova and, as a consequence, to have favored the production of larger zygotes that underwent postzygotic division to produce diploid sporophytes.
Collapse
Affiliation(s)
- David Haig
- Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, Massachusetts 02138 USA
| |
Collapse
|
20
|
Niklas KJ, Kutschera U. Amphimixis and the individual in evolving populations: does Weismann's Doctrine apply to all, most or a few organisms? Naturwissenschaften 2014; 101:357-72. [PMID: 24633620 DOI: 10.1007/s00114-014-1164-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Revised: 02/19/2014] [Accepted: 02/21/2014] [Indexed: 11/24/2022]
Abstract
The German biologist August Weismann (1834-1914) proposed that amphimixis (sexual reproduction) creates variability for natural selection to act upon, and hence he became one of the founders of the Neo-Darwinian theory of biological evolution. He is perhaps best known for what is called "Weismann's Doctrine" or "Weismann's Barrier" (i.e. the irreversible separation of somatic and germ cell functionalities early during ontogeny in multicellular organisms). This concept provided an unassailable argument against "soft inheritance" sensu Lamarck and informed subsequent theorists that the only "individual" in the context of evolution is the mature, reproductive organism. Herein, we review representative model organisms whose embryology conforms to Weismann's Doctrine (e.g. flies and mammals) and those that do not (e.g. freshwater hydroids and plants) based on this survey and the Five Kingdoms of Life scheme; we point out that most species (notably bacteria, fungi, protists and plants) are "non-Weismannian" in ways that make a canonical definition of the "individual" problematic if not impossible. We also review critical life history functional traits that allow us to create a matrix of all theoretically conceivable life cycles (for eukaryotic algae, embryophytes, fungi and animals), which permits us to establish where this scheme Weismann's Doctrine holds true and where it does not. In addition, we argue that bacteria, the dominant organisms of the biosphere, exist in super-cellular biofilms but rarely as single (planktonic) microbes. Our analysis attempts to show that competition among genomic variants in cell lineages played a critical part in the evolution of multicellularity and life cycle diversity. This feature was largely ignored during the formulation of the synthetic theory of biological evolution and its subsequent elaborations.
Collapse
Affiliation(s)
- Karl J Niklas
- Department of Plant Biology, Cornell University, Ithaca, NY, 14893, USA,
| | | |
Collapse
|
21
|
Genome-wide gene expression effects of sex chromosome imprinting in Drosophila. G3-GENES GENOMES GENETICS 2014; 4:1-10. [PMID: 24318925 PMCID: PMC3887524 DOI: 10.1534/g3.113.008029] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Imprinting is well-documented in both plant and animal species. In Drosophila, the Y chromosome is differently modified when transmitted through the male and female germlines. Here, we report genome-wide gene expression effects resulting from reversed parent-of-origin of the X and Y chromosomes. We found that hundreds of genes are differentially expressed between adult male Drosophila melanogaster that differ in the maternal and paternal origin of the sex chromosomes. Many of the differentially regulated genes are expressed specifically in testis and midgut cells, suggesting that sex chromosome imprinting might globally impact gene expression in these tissues. In contrast, we observed much fewer Y-linked parent-of-origin effects on genome-wide gene expression in females carrying a Y chromosome, indicating that gene expression in females is less sensitive to sex chromosome parent-of-origin. Genes whose expression differs between females inheriting a maternal or paternal Y chromosome also show sex chromosome parent-of-origin effects in males, but the direction of the effects on gene expression (overexpression or underexpression) differ between the sexes. We suggest that passage of sex chromosome chromatin through male meiosis may be required for wild-type function in F1 progeny, whereas disruption of Y-chromosome function through passage in the female germline likely arises because the chromosome is not adapted to the female germline environment.
Collapse
|
22
|
Patten MM, Ubeda F, Haig D. Sexual and parental antagonism shape genomic architecture. Proc Biol Sci 2013; 280:20131795. [PMID: 24026821 DOI: 10.1098/rspb.2013.1795] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Populations with two sexes are vulnerable to a pair of genetic conflicts: sexual antagonism that can arise when alleles have opposing fitness effects on females and males; and parental antagonism that arises when alleles have opposing fitness effects when maternally and paternally inherited. This paper extends previous theoretical work that found stable linkage disequilibrium (LD) between sexually antagonistic loci. We find that LD is also generated between parentally antagonistic loci, and between sexually and parentally antagonistic loci, without any requirement of epistasis. We contend that the LD in these models arises from the admixture of gene pools subject to different selective histories. We also find that polymorphism maintained by parental antagonism at one locus expands the opportunity for polymorphism at a linked locus experiencing parental or sexual antagonism. Taken together, our results predict the chromosomal clustering of loci that segregate for sexually and parentally antagonistic alleles. Thus, genetic conflict may play a role in the evolution of genomic architecture.
Collapse
Affiliation(s)
- Manus M Patten
- Department of Biology, Georgetown University, , Washington DC, USA, School of Biological Sciences, Royal Holloway, University of London, , Egham, UK, Department of Organismic and Evolutionary Biology, Harvard University, , Cambridge, MA, USA
| | | | | |
Collapse
|
23
|
O’Donoghue MT, Chater C, Wallace S, Gray JE, Beerling DJ, Fleming AJ. Genome-wide transcriptomic analysis of the sporophyte of the moss Physcomitrella patens. JOURNAL OF EXPERIMENTAL BOTANY 2013; 64:3567-81. [PMID: 23888066 PMCID: PMC3745722 DOI: 10.1093/jxb/ert190] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Bryophytes, the most basal of the extant land plants, diverged at least 450 million years ago. A major feature of these plants is the biphasic alternation of generations between a dominant haploid gametophyte and a minor diploid sporophyte phase. These dramatic differences in form and function occur in a constant genetic background, raising the question of whether the switch from gametophyte-to-sporophyte development reflects major changes in the spectrum of genes being expressed or alternatively whether only limited changes in gene expression occur and the differences in plant form are due to differences in how the gene products are put together. This study performed replicated microarray analyses of RNA from several thousand dissected and developmentally staged sporophytes of the moss Physcomitrella patens, allowing analysis of the transcriptomes of the sporophyte and early gametophyte, as well as the early stages of moss sporophyte development. The data indicate that more significant changes in transcript profile occur during the switch from gametophyte to sporophyte than recently reported, with over 12% of the entire transcriptome of P. patens being altered during this major developmental transition. Analysis of the types of genes contributing to these differences supports the view of the early sporophyte being energetically and nutritionally dependent on the gametophyte, provides a profile of homologues to genes involved in angiosperm stomatal development and physiology which suggests a deeply conserved mechanism of stomatal control, and identifies a novel series of transcription factors associated with moss sporophyte development.
Collapse
Affiliation(s)
| | - Caspar Chater
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK
| | - Simon Wallace
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK
| | - Julie E. Gray
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK
| | - David J. Beerling
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK
| | - Andrew J. Fleming
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK
| |
Collapse
|
24
|
Haig D. Filial mistletoes: the functional morphology of moss sporophytes. ANNALS OF BOTANY 2013; 111:337-45. [PMID: 23277472 PMCID: PMC3579447 DOI: 10.1093/aob/mcs295] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Accepted: 11/19/2012] [Indexed: 05/04/2023]
Abstract
BACKGROUND A moss sporophyte inherits a haploid set of genes from the maternal gametophyte to which it is attached and another haploid set of genes from a paternal gametophyte. Evolutionary conflict is expected between genes of maternal and paternal origin that will be expressed as adaptations of sporophytes to extract additional resources from maternal gametophytes and adaptations of maternal gametophytes to restrain sporophytic demands. INTERPRETATION The seta and stomata of peristomate mosses are interpreted as sporophytic devices for increasing nutrient transfer. The seta connects the foot, where nutrients are absorbed, to the developing capsule, where nutrients are needed for sporogenesis. Its elongation lifts stomata of the apophysis above the boundary layer, into the zone of turbulent air, thereby increasing the transpirational pull that draws nutrients across the haustorial foot. The calyptra is interpreted as a gametophytic device to reduce sporophytic demands. The calyptra fits tightly over the intercalary meristem of the sporophytic apex and prevents lateral expansion of the meristem. While intact, the calyptra delays the onset of transpiration. PREDICTIONS Nutrient transfer across the foot, stomatal number and stomatal aperture are predicted to be particular arenas of conflict between sporophytes and maternal gametophytes, and between maternal and paternal genomes of sporophytes.
Collapse
Affiliation(s)
- David Haig
- Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA 02138, USA.
| |
Collapse
|
25
|
Ligrone R, Duckett JG, Renzaglia KS. The origin of the sporophyte shoot in land plants: a bryological perspective. ANNALS OF BOTANY 2012; 110:935-41. [PMID: 22875816 PMCID: PMC3448429 DOI: 10.1093/aob/mcs176] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Accepted: 05/31/2012] [Indexed: 05/03/2023]
Abstract
BACKGROUND Land plants (embryophytes) are monophyletic and encompass four major clades: liverworts, mosses, hornworts and polysporangiophytes. The liverworts are resolved as the earliest divergent lineage and the mosses as sister to a crown clade formed by the hornworts and polysporangiophytes (lycophytes, monilophytes and seed plants). Alternative topologies resolving the hornworts as sister to mosses plus polysporangiophytes are less well supported. Sporophyte development in liverworts depends only on embryonic formative cell divisions. A transient basal meristem contributes part of the sporophyte in mosses. The sporophyte body in hornworts and polysporangiophytes develops predominantly by post-embryonic meristematic activity. SCOPE This paper explores the origin of the sporophyte shoot in terms of changes in embryo organization. Pressure towards amplification of the sporangium-associated photosynthetic apparatus was a major driver of sporophyte evolution. Starting from a putative ancestral condition in which a transient basal meristem produced a sporangium-supporting seta, we postulate that in the hornwort-polysporangiophyte lineage the basal meristem acquired indeterminate meristematic activity and ectopically expressed the sporangium morphogenetic programme. The resulting sporophyte body plan remained substantially unaltered in hornworts, whereas in polysporangiophytes the persistent meristem shifted from a mid-embryo to a superficial position and was converted into an ancestral shoot apical meristem with the evolution of sequential vegetative and reproductive growth. CONCLUSIONS The sporophyte shoot is interpreted as a sterilized sporangial axis interpolated between the embryo and the fertile sporangium. With reference to the putatively ancestral condition found in mosses, the sporophyte body plans in hornworts and polysporangiophytes are viewed as the product of opposite heterochronic events, i.e. an anticipation and a delay, respectively, in the development of the sporangium. In either case the result was a pedomorphic sporophyte permanently retaining juvenile characters.
Collapse
Affiliation(s)
- Roberto Ligrone
- Dipartimento di Scienze ambientali, Seconda Università di Napoli, Caserta, Italy.
| | | | | |
Collapse
|
26
|
Li J, Berger F. Endosperm: food for humankind and fodder for scientific discoveries. THE NEW PHYTOLOGIST 2012; 195:290-305. [PMID: 22642307 DOI: 10.1111/j.1469-8137.2012.04182.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The endosperm is an essential constituent of seeds in flowering plants. It originates from a fertilization event parallel to the fertilization that gives rise to the embryo. The endosperm nurtures embryo development and, in some species including cereals, stores the seed reserves and represents a major source of food for humankind. Endosperm biology is characterized by specific features, including idiosyncratic cellular controls of cell division and epigenetic controls associated with parental genomic imprinting. This review attempts a comprehensive summary of our current knowledge of endosperm development and highlights recent advances in this field.
Collapse
Affiliation(s)
- Jing Li
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, 117604 Singapore
| | - Frédéric Berger
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, 117604 Singapore
- Department of Biological Sciences, National University of Singapore, Singapore
| |
Collapse
|
27
|
|
28
|
Schmidt A, Schmid MW, Grossniklaus U. Analysis of plant germline development by high-throughput RNA profiling: technical advances and new insights. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2012; 70:18-29. [PMID: 22449040 DOI: 10.1111/j.1365-313x.2012.04897.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Reproduction is a crucial step in the life cycle of plants. The male and female germline lineages develop in the reproductive organs of the flower, which in higher plants are the anthers and ovules, respectively. Development of the germline lineage initiates from a dedicated sporophytic cell that undergoes meiosis to form spores that subsequently give rise to the gametophytes through mitotic cell divisions. The mature male and female gametophytes harbour the male (sperm cells) and female gametes (egg and central cell), respectively. Those unite during double fertilization to initiate embryo and endosperm development in sexually reproducing higher plants. While cytological changes involved in development of the germline lineages have been well characterized in a number of species, investigation of the transcriptional basis underlying their development and the specification of the gametes proved challenging. This is largely due to the inaccessibility of the cells constituting the germline lineages, which are enclosed by sporophytic tissues. Only recently, these technical limitations could be overcome by combining new methods to isolate the relevant cells with powerful transcriptional profiling methods, such as microarrays or high-throughput sequencing of RNA. This review focuses on these technical advances and the new insights gained from them concerning the transcriptional basis and molecular mechanisms underlying germline development.
Collapse
Affiliation(s)
- Anja Schmidt
- Institute of Plant Biology and Zürich-Basel Plant Science Center, University of Zürich, Zollikerstrasse 107, Zürich, Switzerland.
| | | | | |
Collapse
|
29
|
Shaw AJ, Szövényi P, Shaw B. Bryophyte diversity and evolution: windows into the early evolution of land plants. AMERICAN JOURNAL OF BOTANY 2011; 98:352-69. [PMID: 21613131 DOI: 10.3732/ajb.1000316] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The "bryophytes" comprise three phyla of plants united by a similar haploid-dominant life cycle and unbranched sporophytes bearing one sporangium: the liverworts (Marchantiophyta), mosses (Bryophyta), and hornworts (Anthocerophyta). Combined, these groups include some 20000 species. As descendents of embryophytes that diverged before tracheophytes appeared, bryophytes offer unique windows into the early evolution of land plants. We review insights into the evolution of plant life cycles, in particular the elaboration of the sporophyte generation, the major lineages within bryophyte phyla, and reproductive processes that shape patterns of bryophyte evolution. Recent transcriptomic work suggests extensive overlap in gene expression in bryophyte sporophytes vs. gametophytes, but also novel patterns in the sporophyte, supporting Bower's antithetic hypothesis for origin of alternation of generations. Major lineages of liverworts, mosses, and hornworts have been resolved and general patterns of morphological evolution can now be inferred. The life cycles of bryophytes, arguably more similar to those of early embryophytes than are those in any other living plant group, provide unique insights into gametophyte mating patterns, sexual conflicts, and the efficacy and effects of spore dispersal during early land plant evolution.
Collapse
Affiliation(s)
- A Jonathan Shaw
- Department of Biology, Duke University, Durham, North Carolina 27708, USA.
| | | | | |
Collapse
|
30
|
Zhang HY, Xu PZ, Yang H, Wu XJ. [Imprinting genes and it's expression in Arabidopsis]. YI CHUAN = HEREDITAS 2010; 32:670-6. [PMID: 20650847 DOI: 10.3724/sp.j.1005.2010.00670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Genomic imprinting refers to the phenomenon that the expression of a gene copy depends on its parent of origin. The Arabidopsis imprinted FIS (Fertilisation-independent seed) genes, mea, fis2, and fie, play essential roles in the repression of central cell and the regulation of early endosperm development. fis mutants display two phenotypes: autonomous diploid endosperm development when fertilization is absent and un-cellularised endosperm formation when fertilization occurs. The FIS Polycomb protein complex including the above three FIS proteins catalyzes histone H3 K27 tri-methylation on target loci. DME (DEMETER), a DNA glycosylase, and AtMET1 (Methyltransferase1), a DNA methyltransferase, are involved in the regulation of imprinted expression of both mea and fis2. This review summarizes the studies on the Arabidopsis imprinted FIS genes and other related genes. Recent works have shown that the insertion of transposons may affect nearby gene expression, which may be the main driving force behind the evolution of genomic imprinting. This summary covers the achievements on Arabidopsis imprinted genes will provide important information for studies on genomic imprinting in the important crops such as rice and maize.
Collapse
Affiliation(s)
- Hong-Yu Zhang
- Rice Research Institute of Sichuan Agricultural University, Wenjiang 611130, China.
| | | | | | | |
Collapse
|
31
|
Abstract
Flowering plant reproduction is characterized by double fertilization, in which two diminutive brother sperm cells initiate embryo and endosperm. The role of the male gamete, although studied structurally for over a century at various levels, is still being explored on a molecular and cellular level. The potential of the male to influence development has been historically underestimated and the reasons for this are obvious: limitations provided by maternal imprinting, the much greater cellular volume of female gametes and the general paucity of paternal effects. However, as more is known about molecular expression of chromatin-modifying proteins, ubiquitin pathway proteins and transcription factors in sperm cells, as well as their ability to achieve effect by intaglio expression, passing transcripts directly into translation, the role of the male is likely to expand. Much of the expression in the male germline that appears to be distinct from patterns of pollen vegetative cell expression may be the result of chromosomal level regulation of transcription.
Collapse
|
32
|
Dickinson HG, Grant-Downton R. Bridging the generation gap: flowering plant gametophytes and animal germlines reveal unexpected similarities. Biol Rev Camb Philos Soc 2009; 84:589-615. [DOI: 10.1111/j.1469-185x.2009.00088.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
|
33
|
Szövényi P, Ricca M, Shaw AJ. Multiple paternity and sporophytic inbreeding depression in a dioicous moss species. Heredity (Edinb) 2009; 103:394-403. [PMID: 19623211 DOI: 10.1038/hdy.2009.82] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Multiple paternity (polyandry) frequently occurs in flowering plants and animals and is assumed to have an important function in the evolution of reproductive traits. Polyandry in bryophytes may occur among multiple sporophytes of a female gametophyte; however, its occurrence and extent is unknown. In this study we investigate the occurrence and extent of multiple paternity, spatial genetic structure, and sporophytic inbreeding depression in natural populations of a dioicous bryophyte species, Sphagnum lescurii, using microsatellite markers. Multiple paternity is prevalent among sporophytes of a female gametophyte and male genotypes exhibit significant skew in paternity. Despite significant spatial genetic structure in the population, suggesting frequent inbreeding, the number of inbred and outbred sporophytes was balanced, resulting in an average fixation coefficient and population level selfing rate of zero. In line with the prediction of sporophytic inbreeding depression sporophyte size was significantly correlated with the level of heterozygosity. Furthermore, female gametophytes preferentially supported sporophytes with higher heterozygosity. These results indicate that polyandry provides the opportunity for postfertilization selection in bryophytes having short fertilization distances and spatially structured populations facilitating inbreeding. Preferential maternal support of the more heterozygous sporophytes suggests active inbreeding avoidance that may have significant implications for mating system evolution in bryophytes.
Collapse
Affiliation(s)
- P Szövényi
- Department of Biology, Duke University, 139 Biological Sciences Bldg., Box 90338, Durham, NC 27708, USA.
| | | | | |
Collapse
|
34
|
Abstract
Intralocus sexual conflict occurs when populations segregate for alleles with opposing fitness consequences in the two sexes. This form of selection is known to be capable of maintaining genetic and fitness variation in nature, the extent of which is sensitive to the underlying genetics. We present a one-locus model of a haploid maternal effect that has sexually antagonistic consequences for offspring. The evolutionary dynamics of these maternal effects are distinct from those of haploid direct effects under sexual antagonism because the relevant genes are expressed only in females. Despite this, we find the same opportunity for sexually antagonistic polymorphism at the maternal effect locus as at a direct effect locus. Thus, sexually antagonistic maternal effects may underlie some natural genetic variation. The model we present permits alternative interpretations of how the genes are expressed and how the fitness variation is assigned, which invites a theoretical comparison to models of both imprinted genes and sex allocation.
Collapse
Affiliation(s)
- Manus M Patten
- Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA 02138, USA.
| | | |
Collapse
|
35
|
Immler S. Sperm competition and sperm cooperation: the potential role of diploid and haploid expression. Reproduction 2008; 135:275-83. [PMID: 18299420 DOI: 10.1530/rep-07-0482] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Sperm competition is a powerful selective force driving the evolution of sperm shape and function. Recent findings suggest that sperm cooperation is a potential evolutionary response to sperm competition. Sperm cooperation may enhance the performance of the ejaculate increasing a male's chance to outcompete rival males in competition for fertilisation. Whether and how sperm cooperation may evolve is the focal point of this review. The relative importance of haploid and diploid gene expression for the evolution of sperm cooperation and the potential conflict of interest between (i) haploid sperm and diploid male and (ii) among sibling sperm, since sibling sperm only share an average of 50% of their genes in a diploid organism, are discussed. Furthermore, sperm cooperation is defined and the literature for empirical evidence of sperm cooperation is reviewed in light of the author's definitions.
Collapse
Affiliation(s)
- Simone Immler
- Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield S10 2TN, UK.
| |
Collapse
|
36
|
Huh JH, Bauer MJ, Hsieh TF, Fischer R. Endosperm gene imprinting and seed development. Curr Opin Genet Dev 2007; 17:480-5. [PMID: 17962010 DOI: 10.1016/j.gde.2007.08.011] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2007] [Accepted: 08/24/2007] [Indexed: 11/24/2022]
Abstract
Imprinting occurs in the endosperm of flowering plants. Endosperm, produced by fertilization of the central cell in the female gametophyte, is essential for embryo and seed development. Several imprinted genes play an important role in endosperm development. The mechanism of gene imprinting involves DNA methylation and histone modification. DNA methylation is actively removed at the imprinted alleles to be activated. Histone methylation mediated by the Polycomb group complex provides another layer of epigenetic regulation at the silenced alleles. Endosperm gene imprinting can be uncoupled from seed development when fertilization of the central cell is prevented. Imprinting may be a mechanism to ensure fertilization of the central cell thereby preventing parthenogenic development of the endosperm.
Collapse
Affiliation(s)
- Jin Hoe Huh
- University of California at Berkeley, Plant & Microbial Biology Department, Berkeley, CA 94720-3102, USA
| | | | | | | |
Collapse
|
37
|
Affiliation(s)
- N G Prasad
- Department of Biology, Queen's University at Kingston, Biosciences Complex, 116 Barrie Street, Kingston, Ontario K7L 3N6, Canada.
| | | |
Collapse
|
38
|
Abstract
Sexual conflict arises from differences in the evolutionary interests of males and females and can occur over traits related to courtship, mating and fertilisation through to parental investment. Theory shows that sexual conflict can lead to sexually antagonistic coevolution (SAC), where adaptation in one sex can lead to counter-adaptation in the other. Thus, sexual conflict can lead to evolutionary change within species. In addition, SAC can--through its effects on traits related to the probability of mating and of zygote formation--potentially lead to reproductive isolation. In this review, I discuss that, although sexual conflict is ubiquitous, the actual expression of sexual conflict leading to SAC is less frequent. The balance between the benefits and costs of the manipulation of one sex by the other, and the availability of mechanisms by which conflict is expressed, determine whether actual sexual conflict is likely to occur. New insights address the relationship between sexual conflict and conflict resolution, adaptation, sexual selection and fitness. I suggest that it will be useful to examine systematically the parallels and contrasts between sexual and other evolutionary conflicts. Understanding why some traits, but not others, are subject to evolutionary change by SAC will require data on the mechanisms of the traits involved and on the relative benefits and costs of manipulation and resistance to manipulation.
Collapse
Affiliation(s)
- Tracey Chapman
- School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK.
| |
Collapse
|
39
|
Tregenza T, Wedell N, Chapman T. Introduction. Sexual conflict: a new paradigm? Philos Trans R Soc Lond B Biol Sci 2006; 361:229-34. [PMID: 16612883 PMCID: PMC1569611 DOI: 10.1098/rstb.2005.1796] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Affiliation(s)
- T Tregenza
- Centre for Ecology and Conservation, University of Exeter in Cornwall, Tremough Campus, UK
| | | | | |
Collapse
|